Mixed ester-metal salts and lubricants and fuels containing the same

ABSTRACT

LUBRICATING AND FUEL COMPOSITIONS COMPRISING A MAJOR AMOUNT OF A LUBRICATING OIL AND A MINOR PROPORTION OF AN ESTER DERIVATIVE OF A HYDROCARBON-SUBSTITUTED SUCCINIC ACID WHEREIN THE HYDROCARBON SUBSTITUENT CONTAINS AT LEAST ABOUT FIFTY ALIPHATIC CARBON ATOMS, THE SUBSTITUENT BEING FURTHER CHARACTERIZED BY HAVING NO MORE THAN ABOUT 5% OLEFINIC LINKAGES THEREIN BASED ON THE TOTAL NUMBER OF CARBON-TO-CARBON COVALENT LINKAGES IN THE SUBSTITUENT. THE ESTERS INCLUDE THE ACIDIC ESTERS, DIESTERS, MIXED ESTER-METAL SALTS, AND MIXTURES OF THESE WHEREIN THE ESTER MOIETY IS DERIVED FROM MONOHYDRIC AND POLYHYDRIC ALCOHOLS, PHENOLS, NAPTHTHOLS, AND THE LIKE.

3,632,510 Patented Jan. 4, 1972 United States Patent Office 3,632,510 MIXED ESTER-METAL SALTS AND LUBRICANTS AND FUELS CONTAINING THE SAME William Monroe LeSuer, Cleveland, Ohio, assignor to The LubrizolCorporation, Wicklifie, Ohio No Drawing. Continuation-impart of application Ser. No.

567,052, July 22, 1966, now Patent No. 3,522,179, which is a continuation-impart of application Ser. No. 274,905, Apr. 23, 1963. This application Feb. 13, 1970, Ser. No. 11,335

Int. Cl. C101 1/18; Cm 1/26', l/54 US. Cl. 252-35 26 Claims ABSTRACT OF THE DISCLOSURE This is a continuation-in-part of application Ser. No.

567,052, filed July 22, 1966 now US. Pat. 3,522,179,

which in turn is a continuation-in-part of Ser. No. 274,905, filed Apr. 23, 1963, now abandoned.

This invention relates to novel compositions of matter and proceses for preparing the same. In a more particular sense this invention relates to compositions useful as plasticizers, detergents, anti-trust agents, emulsifiers, and addi-, tives in lubricating compositions, fuels, hydrocarbon oils, and power transmitting fluids. I

Deterioration of lubricating oils, especially mineral oils,

I has beena great concern in the formulation of lubricating compositions for use in internal combustion engines, transmissions, gears, etc., Deterioration of the oil results in the formation of products which are corrosive to the metal surfaces with which the oil comes into contact. It also results in the formation of products which agglomerate to form sludgeand varnish-like deposits. The deposits cause sticking of the moving metal parts and obstruct their free movement. They are a principal cause of malfunctioning and premature break-down of the equipment which the oil lubricates.

It is known that water is a common contaminant in the crankcase lubricant of an engine. It may result from the decomposition of the lubricating oil or come from the combustion chamber as a blow-by product of the burning of the fuel. The presence of water in the lubricant seems to promote the deposition of a mayonnaise-like sludge. This type of sludge is more objectionable because it clings tenaciously to metal surfaces and is not removed by oil filters. If the engine is operated under conditions such that the crankcase lubricant temperature is continuously high the Water will be eliminated about as fast as it accumulates and only a very small amount of the mayonnaise-like sludge will be formed. 'On the other hand, if the crankcase lubricant temperature is intermittently high and low or consistently low the water will accumulate and a substantial quantity of the mayonnaise-like sludge will be deposited in the engine.

High operating temperatures are characteristic of an engine that is run consistently at a relatively high speed. However, where an automobile is used primarily for trips of short distance such as is characteristic of urban, home provide novel compositions of matter.

to Work use, a significant portion of the operation occurs before the engine has reached its optimum high temperature. An ideal environment thus obtains for the accumulation of water in the lubricant. In this type of operation the problem of mayonnaise-like sludge has been especially troublesome. Its solution has been approached by the use in the lubricant of detergents such as metal phenates and sulfonates whichliave been known to be effective infreduc ing deposits'in engines operated primarily at high tentperatures, Unfortunately,'such known detergents have not been particularly effectivein solving the problems asso ciated with low temperature operation particularly those problems which are associated with crankcase lubricants in engines operated at low or intermittently high and low temperatures. I

It is accordingly a principal object of this invention to It is also an object ofthis invention to oils.

It is also an objectlof this invention to provide com positions which are effective as additives in lubricating compositions.

It is another object of this invention to provide cornpo'sitions effective as detergents in lubricating compositions intended for use in engines operated at low or intermit-.

tently high and low temperatures.

It is another object of this invention to provide a process of preparing additives useful as additives in hydrocarbon oils and lubricating compositions.

It is another object of this invention to provide lubricat-l ing compositions.

It is further an object of compositions.

These and other objects are attained in accordance with this invention by means of. an'ester' of a substantially saturated hydrocarbon-substituted succinic acid wherein the substantially saturated hydrocarbon substituent has at least about fifty aliphatic carbon atoms. A critical aspect.

of this invention is the size and the chemical constitution of the substantially saturated hydrocarbon substituent of the succinic radical. Thus, only the esters of substituted succinic acids in which the substituent is substantially saturated and has at least about fifty aliphatic carbon atoms are contemplated as being within the scope of this invention. By substantially saturated, I intend to limit the hydrocarbon substituent to those wherein not more than about 5%, preferably 2%, of the total number of.

carbon-to-carbon covalent bonds therein are unsaturated linkages such as ethylenic linkages, C=C This lower limit for the size of the substitutent is based upon a consideration not only of the oil-solubility of the esters but also of their effectiveness in applications contemplated by this invention.

It is contemplated that the substantially saturated hydrocarbon substitutent of the succinic radical may contain polar groups, provided, however, that the polar groups are not present in proportions sufficiently large' to alter significantly the hydrocarbon character of the substituent. The polar groups are exemplified by halo, e.g., chloro, bromo, and iodo; keto, ether, aldehyde, thio, sulfinyl, sulfonyl, nitro, etc., groups. The upper limit with respect to such polar groups in the substituent is approximately 10% based on the weight of the hydrocarbon portion of the substituent.

The sources of the substantially saturated hydrocarbon substituent include principally the high molecular weight substantially saturated petroleum fractions and substantially saturated olefin polymers, particularly polymers of monoolefins having from two to thirty carbon atoms. The especially useful polymers are the polymers of l-monoolefins such as ethylene, propene, l-butene, isobutene, l-

provide composi' tions which are suitable for use as additive-s in hydrocarbon this invention to provide fueli 3 hexene, l-octene, Z-rnethyl-l-heptene, 3-cyclohexyl-l-butene, and 2-methyl-5-propyl-1-hexene. Polyisobutylene is the most preferred source of the hydrocarbon substituent.

finic linkage is not at the terminal position, likewise are useful. They are illustrated by 2-butene, 3-pentene, and 4-octene.

Also useful are the interpolymers of the olefins such as those illustrated above with other interpolymerizable olefinic substances such as aromatic olefins, cyclic olefins, and polyolefins. Such interpolymers include, for example, those prepared by polymerizing isobutene with styrene; isobutene with butadiene; propene with isoprene; ethylene with piperylene; isobutene with chloroprene; isobutene with p-methyl styrene; l-hexene with 1,3-hexadiene; 1- octene with l-hexene; l-heptene With l-pentene; 3-methyl-l-butene with l-octene; 3,3-dimethyl-1-pentene with 1- hexene; isobutene with styrene and piperylene, etc.

The relative proportions of the monoolefins to the other monomers in the interpolymers influence the stability and oil-solubiilty of the final products derived from such interpolymers. Thus, for reasons of oil-solubility and stability the interpolymers contemplated for use in this invention should be substantially aliphatic and substantially saturated, i.e., they should contain at least about 80%, preferably at least about 95%, on a weight basis, of units derived from the aliphatic monoolefins and no more than about 5% of olefinic linkages based on the total number of carbon-to-carbon covalent linkages. In most instances, the percentage of olefinic linkages should be less than about 2% of the total number of carbon-to-carbon covalent linkages.

Specific examples of such interpolymers include the copolymer of 95% (by Weight) of isobutene with 5% of styrene; the terpolymer of 98% of isobutene with 1% of piperylene and 1% of chloroprene; the terpolymer f 95% of isobutene with 2% of l-butene and 3% of 1- hexene; the terpolymer of 80% of isobutene with 10% of l-pentene and 10% of l-octene; the copolymer of 80% of l-hexene and 20% of l-heptene; the terpolymer of 90% of isobutene with 2% of cyclohexene and 8% of propene; and the copolymer of 80% of ethylene and 20% of propene.

Another source of the substantially saturated hydrocarbon radical comprises saturated aliphatic hydrocarbons such as highly refined high molecular weight white oils or synthetic alkanes such as are obtained by hydrogenation of high molecular weight olefin polymers illustrated above or high molecular weight olefinic substances.

The olefin polymers having average molecular weights of about 700-5000 are the preferred source of the substantially saturated hydrocarbon substituent. Higher molecular Weight olefin polymers having average molecular.

weights from about 10,000 to about 100,000 or higher have been found to impart viscosity index improving properties to the final products of this invention. Thus the use of such higher molecular weight olefin polymers often is desirable.

The esters of this invention are those of the abovedescribed substituted succinic acids with hydroxy compounds which may be aliphatic compounds such as monohydric and polyhydric alcohols and aromatic compounds such as phenols and naphthols. The aromatic hydroxy compounds from which the esters of this invention may be derived are illustrated hereafter. Generally, the nucleus of the monoand polyhydric hydroxy aromatic com pounds will be a benzene ring or an aromatic condensed hydrocarbon ring such as naphthalene. Monohydric and polyhydric phenols, and naphthols are preferred hydroxy aromatic compounds. These hydroxy-su-bstituted aromatic compounds may contain other substituents in addition to the hydroxy substituents such as halo, alkyl, alkenyl, a1- koxy, nitro, and the like. Usually, the hydroxy aromatic compound will contain one to four hydroxy groups. The aromatic hydroxy compounds from which the esters of this invention may be derived are illustrated by the following specific examples: phenol, p-chlorophqgl pflilltihw phenol,.hetanaph-thel alphaunaphtholfcre'sols, resorcinol,

catechol, carvacrol, thymol, eugenol, p,p-dihydroxybiphenyl, hydroquinone, pyrogallol, phloroglucinol, hexylresorcinol, orcin, guaiacol, 2-chlorophenol, 2,4-dibutylphenol, propene tetramer-substituted phenol, didodecylphenol, 4,4-methylene-bis-phenol, alpha-decyl-beta-naphthol, polyisobutene-(molecular weight of 1000)-substitut- 10 ed phenol, the condensation product of heptylphenol with 0.5 mole of formaldehyde, the condensation product of octylphenol with acetone, di(hydroxyphenyl)oxide, di(hydroxyphenyl)sulfide, di(hydroxyphenyl)disulfide, and 4 cyclohexylphenol. Phenol and aliphatic hydrocarbon substituted phenols, e.g., alkylated phenols, having up to three aliphatic hydrocarbon substituents are especially preferred. Each of the aliphatic hydrocarbon substituents may contain 100 or more carbon atoms but usually will have from one to twenty carbon atoms. Alkyl and alkenyl groups are the preferred aliphatic hydrocarbon substituents.

The alcohols from which the esters may be derived preferably contain up to about forty carbon atoms. They may be monohydric alcohols such as methanol, ethanol, isooctanol, dodecanol, cyclohexanol, cyclopentanol, behenyl alcohol, hexatriacontanol, neopentyl alcohol, isobutyl alcohol, benzyl alcohol, beta-phenylethyl alcohol, 2- methylcyclohexanol, beta-chloroethanol, monomethyl ether of ethylene glycol, monobutyl ether of ethylene glycol, monopropyl ether of diethylene glycol, monododecyl ether of triethylene glycol, mono-oleate of ethylene glycol, monostearate of diethylene glycol, sec-pentyl alcohol, tert-butyl alcohol, 5-bromo-dodecanol, nitro-octadecanol and dioleate of glycerol.

However, esters derived from polyhydric alcohols constitute a preferred aspect of my invention. The polyhydric alcohols preferably contain from two to about ten hydroxy radicals. They are illustrated by, for example, alkylene glycols in which the alkylene radical contains from two to about eight carbon atoms. Other useful polyhydric alcohols include glycerol, monooleate of glycerol, monostearate of glycerol, monomethyl ether of glycerol, pentaerythritol, 9,10-dihydroxystearic acid, 3-chloro-1,2-propanediol, 1,2-butanediol, 1,4-butanediol, 2,3-hexanediol, 2,4-

hexanediol, pinacol, erythritol, ara'bital, sorbitol, mannitol,

1,2-cycl-ohexanediol, 1,4-cyclohexanediol, 1,4-(2-hydroxyethyD-cyclohexane, 1,4-dihydroxy-2-nitro-butane, 1,4-di- (2-hydroxyethyl)-benzene, the carbohydrates such as glucose, hamnose, mannose, glyceraldehyde, and galactose, di(2-hydroxyethyl)amine, tri-(3-hydroxypropyl)- amine, N ,N'-di(hydroxyethyl ethylenediamine, copolymer of allyl alcohol and styrene, etc.

Included within this group of polyhydric alcohols are those polyhydric aliphatic alcohols containing at least three hydroxyl groups, at least one of which has been esterified with a monocar'boxylic acid having from eight to about thirty carbon atoms such as octanoic acid, oleic acid, stearic acid, linoleic acid, dodecanoic acid, or tall oil acid. Examples of such partially esterified polyhydric alcohols are the mono-oleate of sorbitol, sorbitan monooleate, the mono-oleate of glycerol, the monostearate of glycerol, the distearate of sorbitol, and the didodecanoate of erythritol.

A preferred class of esters are those prepared from polyhydric alcohols containing up to ten carbon atoms, and especially those containing three to ten carbon atoms. This class of alcohols includes glycerol, erythritol, pentaeryth'ritol, gluconic acid, glyceraldehyde, glucose, arabinose, l,7-heptanediol, 2,4-heptanediol, 1,2,3-hexanetriol,

1,2,4-hexanetriol, 1,2,5-hexanetriol, 2,3,4-hexanetriol,

1,2,3-butanetriol, 1,2,4-butanetriol, quinic acid, 2,2,6,6- tetrakis- (hydroxymethyl cyclohexanol, 1, 1 O-decanediol, digitalose, and the like. The esters prepared from aliphatic alcohols containing at least three hydroxyl groups and up to ten carbon atoms are particularly preferred.

An especially preferred class of polyhydric alcohols for preparing the esters of my invention are the polyhydric alkanols containing three to ten carbon atoms and particularly, those containing three to six carbon atoms and having at least three hydroxyl groups. Such alcohols are exemplified by glycerol, erythritol, pentaerythritol, mannitol, sorbitol, 2-hydroxyrnet-hyl-2-methyl-l,3-propanediol(trimethylolethane), Z-hydroxymethyl-Z-ethyl-1,3-propanediol(trimethylolpropane), 1,2,4-hexanetriol, and the like.

Other useful polyhydric alcohols include alkylene glycols and polyoxyalkylene glycols such as ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, and polyglycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, tributylene glycol, and other alkylene glycols and polyoxyalkeylene glycols in which the alkylene radical contains from two to about eight carbon atoms. The monoethers of these alkylene glycols and polyoxyalkylene glycols are also useful in preparing esters of the present invention. These include the monoaryl ethers, monoalkyl ethers, and monoaralkyl ethers of these alkylene glycols and polyoxyalkylene glycols. This group of alcohols can be represented by the formula HO Rr-O Rr-ORa where R is hydrogen; aryl such as phenyl, lower alkoxy phenyl, or lower alkyl phenyl; lower alkyl such as ethyl, propyl, tert-butyl, pentyl, etc.; and aralkyl such as benzyl, phenylethyl, phenylpropyl, p-ethylphenylethyl, etc.; 11 is zero to about 150, and R and R are lower alkylene of up to eight, preferably, two to four carbon atoms. 'Polyoxyalkylene glycols where the alkylene groups are ethylene or propylene and m is at least two as well as the monoethers thereof as described above are very useful for preparing esters of this invention.

Amino alcohols contemplated as suitable for preparing the esters can be monohydric or polyhydric. Examples of suitable amino alcohols are the N-(hydroxy-lower alkyl)- amines and polyamines such as 2-hydroxyethylamine, 3- hydroxybutylamine, di-(Z-hydroxylethyl)amine, tri-(2- hydroxyethyl) amine, di- (Z-hydroxypropyl amine, N,N,N- tri-(2-hydroxyethyl)ethylenediamine, N,N,N,N'-tetra-(2- hydroxyethyl)ethylenediamine, N -(2 hydroxyethyl)- piperazine, N,N di (3 hydroxypropyl)piperazine, N (2 hydroxyethyDmorpholine, N (2 hydroxyethyl)- 2-morpholinone, N (2 hydroxyethyl) 3 methyl-2- morpholinone, N (2 hydroxypropyl) 6 methyl-2- morpholinone, N-(2 hydroxyethyl) carbethoxy-Z- piperidone, N-(2 hydroxypropyl) 5 carbethoxy-2- piperidone, N-(2-hydroxyethyl) 5 (N-butylcarbamyl)- 2 piperidone, N-(Z-hydroxyethyl)piperidine, N-(4-hydroxybutyl)piperidine, N,N di-(Z-hydroxyethyl) glycine, and esters thereof with aliphatic alcohols, especially lower alkanols, N,N-di-(3-hydroxypropyl) glycine, and the like. Also contemplated are other monoand poly-N-hydroxyalkyl-substituted alkylene polyarnines wherein the alkylene radicals contain two to four carbon atoms and the polyamine has up to seven amino groups such as the reaction product of 3,5 moles of propylene oxide and the one mole of diethylenetriamine.

The esters of this invention may also be derived from unsaturated alcohols such as allyl alcohol, cinn'amyl alcohol, propargyl alcohol, l-cyclohexene-S-ol, an oleyl alcohol.

The esters of this invention may be diesters of succinic acids or acidic esters, i.e., partially esterified succinic acids where only one carboxyl group of the succinic acid enters into the esterification reaction; as well as partially esterified polyhydric alcohols or phenols, i.e., esters having free alcoholic or phenolic hydroxyl radicals. Mixtures of the above-illustrated esters likewise are contemplated within the scope of this invention.

The esters may be prepared by one of several methods.

The method which is preferred because of convenience and superior properties of the esters it produces, involves the reaction of a suitable alcohol or phenol with a substantially hydrocarbon-substituted succinic anhydride. The esterification is usually carried out at a temperature above about C., preferably between C. and 300 C.

The water formed as a by-product is removed by distillation as the esterification proceeds. A solvent may be used in the esterification to facilitate mixing and temperature control. It also facilitates the removal of water from the reaction mixture. The useful solvents include Xylene, toluene, diphenyl ether chlorobenzene, and mineral oil. The esterification is illustrated by the reaction of ethylene glycol with a substituted succinic anhydride as represented by the equations below.

(III) wherein R is a subtsantially saturated hydrocarbon radical as defined hereinbefore having at least about fifty aliphatic carbon atoms. It will be readily appreciated that the above equations are merely illustrative. Other products not represented by Formulas I, II, and III may be formed. Polymeric esters formed by the condensation of two or more molecules of each of the succinic acid reactant and the polyhydric alcohol reactant likewise may be formed. In most cases the product is a mixture of esters, the precise chemical composition and the relative proportions of which in the product are difiicult to determine. Consequently, the product of such reaction is best described in terms of the process by which it is formed.

A modification of the above process involves the replacement of the substituted succinic anhydride withthe corresponding succinic acid. However, succinic acids readily undergo dehydration at temperatures above about 100 C. and are thus converted to their anhydrides which are then esterified by the reaction with the alcohol reacaEidiTster, diester, etc.) and the number of hydroxyl groups present in the molecule of the hydroxy reactant. For instance, the formation of a half ester of a succinic acid, i.e., an acidic ester or one in which only one of the two carboxyl groups is esterified, involves the use of one mole of a monohydric alcohol for each mole of the substituted succinic acid reactant, whereas the formation of a diester of a succinic acid involves the use of two moles of the alcohol for ecah mole of the acid. On the other hand, one mole of a hexahydric alcohol may combine with as many as six moles of a succinic acid to form an acidic ester in which each of the six hydroxyl radicals of the alcohol is esterified with one of the two acid radicals of the succinic acid. Thus, the maximum amount of succinic acid which can react with a polyhydric alcohol is determined by the number of hydroxyl groups present in the molecule of the hydroxy reactant. For the purposes of this invention, it has been found that esters obtained by the reaction of equimolar amounts of the succinic acid reactant and hydroxy reactant have superior properties and are therefore preferred.

In some instances it is advantageous to carry out the esterification in the presence of a catalyst such as sulfuric acid, pyridine hydrochloride, hydrochloric acid, benzene sulfonic acid, p-toluene sulfonic acid, phosphoric acid, or any other known esterification catalyst. The amount of the catalyst in the reaction may be as little as 0.01% (by weight of the reaction mixture), more often from about 0.1% to about The esters of this invention likewise may be obtained by the reaction of a substituted succinic acid or anhydride with an epoxide or a mixture of an epoxide and water.

.Such reaction is similar to one involving the acid or anhydride with a glycol. For instance, the product represented by the structural Formula I above may be prepared by the reaction of a substituted succinic acid with one mole of ethylene oxide. Similarly, the product of Formula II may be obtained by the reaction of a substituted succinic acid with two moles of ethylene oxide. Other epoxides which are commonly available for use in such reaction include, for example, propylene oxide, styrene oxide, 1,2-butylene oxide, 2,3-butylene oxide, epichlorohydrin, cyclohexene oxide, 1,2-octylene oxide, epoxidized soya bean oil, methyl ester of 9,10-epoxy-stearic acid, and butadiene monoepoxide. For the most part, the epoxides are the alkylene oxides in which the alkylene radical has from two to about eight carbon atoms; or the epoxidized fatty acid esters in which the fatty acid radical has up to about thirty carbon atoms and the ester radical is derived from a lower alcohol having up to about eight carbon atoms.

In lieu of the succinic acid or anhydride, a substituted succinic acid halide may be used in the processes illustrated above for preparing the esters of this invention. Such acid halides may be acid dibromides, acid dichlorides, acid monochlorides, and acid monobromides. The substituted succinic anhydrides and acids can be prepared by, for example, the reaction of maleic anhydride with a high molecular weight olefin or a halogenated hydrocarbon such as is obtained by the chlorination of an olefin polymer described previously. The reaction involves merely heating the reactants at a temperature preferably from about 100 C. to about 250 C. The product from such a reaction is an alkenyl succinic anhydride. The alkenyl group may be hydrogenated to an alkyl group. The anhydride may be hydrolyzed by treatment with water or steam to the corresponding acid. Another method useful for preparing the succinic acids or anhydrides involves the reaction of itaconic acid or anhydride with an olefin or a chlorinated hydrocarbon at a temperature usually within 8 the range from about 100 C. to about 250 C. The succinic acid halides can be prepared by the reaction of the acids or their anhydrides with a halogenation agent such as phosphorus tribronu' lg phosphorus pentachloride, or--- thionylchl'ofide. lhe'se and other methods of preparing the succinic compounds are well-known in the art and need not be illustrated in further detail here.

Still other methods of preparing the esters of this invention are available. For instance, the esters may be obtained by the reaction of maleic acid or anhydride with an alcohol such as is illustrated above to form a monoor diester of maleic acid and then the reaction of this ester with an olefin or a chlorinated hydrocarbon such as is illustrated above. They may also be obtained by first esterifying itaconic anhydrides or acid and subsequently reacting the ester intermediate with an olefin or a chlorinated hydrocarbon under conditions similar to those described hereinabove.

The esters of the particular aspect of my invention claimed herein are referred to as mixed ester-metal salts. By the terminology mixed ester-metal salts I intend to describe that subclass of esters of my invention characterized by the presence within their structure of substantially saturated hydrocarbon-substituted succinic acid molecules wherein one carboxyl group of the succinic acid is esterified with a monoor polyhydric alcohol, phenol, etc., as described fully hereinabove, and the other carboxyl group exists as a metal carboxylate group. Thus, a mixed ester-metal salt as contemplated by this aspect of my invention can be represented by the general formulae:

where R is as defined previously, R is the residue of a monoor polyhydric alcohol or monoor polyhydric hydroxy aromatic compound as described above, and M represents one equivalent of the cation of a metal. While M will usually represent a cation of a Group I or Group II metal, other cations also provide mixed ester-metal salts useful as additives for lubricants and fuels, e.g., M can be a cation of lead, zinc, cadmium, nickel, cobalt, or aluminum. Preferably, however, M will be a cation of zinc or an alkali or alkaline earth metal such as lithium, sodium, potassium, magnesium, calcium, or barium. The alkaline earth metals are especially preferred cations.

As will be apparent to those skilled in the art, especially in view of the foregoing detailed description of the esters of my invention, R may be the residue of a polyhydric alcohol or hydroxy aromatic compound which has been esterified by more than one hydrocarbon-substituted succinic acid acylating agent. For example, in Diagram I, the acidic ester represented by Formula III could be converted to a mixed ester-metal salt ester of the type contemplated herein simply by neutralizing it with a basically reacting alkali metal compound so as to convert one or both of the unesterified carboxyl groups to the corresponding alkali metal carboxylate group. Likewise, it will be apparent to those skilled in the art that when the metal cation is polyvalent, carboxyl groups from two or more different hydrocarbon-substituted succinic acid molecules will be required to form the mixed ester-metal salt contemplated by this invention, the specific number of carboxyl groups depending on the valence of the particular metal.

The mixed ester-metal salts are generally prepared by either of two processes. Preferably, a substantially saturated hydrocarbon-substituted succinic acid acylating agent such as the acid per se, the anhydride, the acid chloride, and the like is reacted with a monoor polyhydric alcohol or aromatic compound under esterification conditions according to the general procedure described hereinabove. The esterification conditions are controlled so that an acidic ester is produced, that is, an esterification product characterized by .the presence of unesterified carboxylic acid acylating groups. The means by which the esterification reaction can be controlled are apparent and within the skill of the art. For example, the ratio of substantially saturated hydrocarbon-substituted succinic acid acylating agent to monoor polyhydric alcohol or aromatic compound can be varied; the temperature and duration of reaction can be increased or decreased as necessary; the amount of esterification catalyst, if any, employed can be increased or decreased as necessary; and the like. Principally, however, all that is required to produce the necessary acidic esters used as intermediates in the preparation of the mixed ester-metal salts is to follow the decrease in acid number during the esterification reaction so that the esterification can be terminated when the desired degree of esterification has been achieved. That is, all one need do is periodically determine the acid number, neutralization equivalent, etc., of the esterification reaction mixture during the esterification reaction and terminate the esterification reaction when the acid number of the esterification mixture indicates the desired degree of esterification has been achieved.

When preparing the acidic ester intermediates, esterifica tion should be continued until about 10% to about 95%, preferably 25% to about 75% of the total number of carboxyl groups of the substantially saturated hydrocarbon-substituted succinic acid acylating agent have been esterified. Then, the resulting acidic ester should be reacted with basically reacting metal compounds to convert the unesterified carboxylic acylating groups to metal carboxylate group. At least about 10% of the remaining unesterifiedcarboxylic acid acrylating groups in the resulting esterification reaction mixture should be converted to the corresponding metal carboxylates and preferably substantially all unesterified carboxylic acid acylating groups will be converted tothe metal salt. At least of the total' tially saturated hydrocarbon-substituted succinic acidacylating agent is first reacted with a basically reacting metal compound until the desired number of the carboxylic acid acrylating groups have been converted to metal carboxylate groups. The resulting acidic metal salt is then reacted with monoand polyhydric alcohols and hydroxy aromatic compounds under esterification conditions as described hereinbefore until at least half of the remaining unreacted carboxylic acylating groups have been esterified and, preferably, until substantially all of the remaining carboxylic acid acylating group have been esterified. Obviously, the initial reaction between the basically reacting metal compound and the substantially saturated hydrocarbon-substituted succinic acid acylating agent can be controlled as described hereinabove by periodically determining the acid number of the reaction mixture during the course of the reaction and ceasing the salt forming reaction and the esterification at the point where the desired number of carboxyl groups have been converted to metal carboxylate groups and carboxylic acid ester groups.

The carboxylic acid acrylating groups are the carboxyl groups of the substantially saturated hydrocarbon-substituted succinic acid acylating agent of their equivalent such as etc.

From the foregoing, it will be apparent to those skilled in the art that the mixed ester-metal salts of the present invention include not only the half ester-half metal salt products but mixtures of such products with diesters and acidic esters. Likewise, metal salts of acidic esters of the type corresponding to Formula .II'I above are within the scope of this invention where either or both of the free carboxyl groups of that ester have been converted to a metal carboxylate group. Obviously, esters prepared from other polyhydric alcohols and aromatic compounds having more than two hydroxy groups ofrer still further variations in the mixed ester-metal salts of this invention. Due to the polyfunctional character of the substantially saturated hydrocarbon-substituted succinic acid acylating agents as well as many of the polyhydric alcohols and aromatic compounds and the polyvalent character of the metal cations contemplated by this invention, specific structures cannot be attributed to the mixed ester-metal salts of this invention. In fact, most of the mixed ester-metal salts prepared according to the processes described herein will be mixtures of various metal carboxylate-containing esters. At least 5% of the total number of carboxyl groups in the mixed ester-metal salt reaction products should be metal carboxylate groups. Up to about may be metal carboxylate groups. Preferably about 10% to about 70% of the total carboxyl groups will be metal carboxylate groups.

Other processes for preparing the mixed ester-metal salts of this invention will be apparent to those skilled in the art in view of the detailed discussion for preparing esters set forth hereinabove. For example, maleic acid can be converted to a half metal salt-half ester and thereafter reacted with chlorinated hydrocarbons such as chlorinated polyisobutylene or a polymerized l-monoolefin such as polyisobutylene to prepare the desired mixed estermetal salt. Similarly, fumaric acid can be reacted with a basically reacting metal compound and the resulting metal salt reacted with chlorinated hydrocarbon or polymerized olefin to prepare the corresponding substantially saturated hydrocarbon-substituted acidic succinic acid salt. The remaining carboxyl groups can then be converted to ester groups by reacting the acidic salt with monoand polyhydric alcoholsand aromatic compounds under esterification conditions as described above. Similarly, maleic acid or maleic anhydride could be converted to an acidic ester, thereafter reacted with the chlorinated hydrocarbon or the polymerized olefin, and the resulting acidic succinic acid ester reacted with basically reacting metal compounds.

In preparing the mixed ester-metal salts, the acidic ester cording to conventional carboxylic acid metal salt forming procedures at a temperature within the range of about 25 C. to about 250 C. but usually within the range of about 80 C. to about 200 C. Substantially inert orgamc diluents such as those described above, e.g., mineral oil, toluene, xylene, cyclohexane, heptane, and the like may be employed during the reaction with the basically reacting metal compounds. The amount of basically reacting metal compound employed in the reaction will depend on the product desired. If all of the unesterified carboxyl groups are to be converted to metal carboxylate groups, then at least a stoichiometrically equivalent amount of basically reacting metal compound will be employed, i.e., one equivalent of metal for each equivalent of unesterified carboxylic acid acylating agent. Obviously, an excess of the basically reacting metal compound facilitates the formation of the desired mixed ester-metal salts although there seems to be no advantage in employing more than a stoichiometric excess of basically reacting metal compound. If it is desired that only a portion of the unesterified carboxyl groups be converted to metal carboxylate groups, then the amount of basically reacting metal compound can be limited to that amount necessary to provide the number of equivalents of metal necessary to react with the desired number of metal carboxylate groups. On theother hand, excess basically reacting metal compound can be used with periodic determinations of the acid number of the product so that the metal salt forming reaction can be terminated when the desired number of carboxylic acid acylating groups have been converted to metal carboxylate groups. Obviously, the same 1 1 considerations apply if the mixed ester-metal salt is prepared by first forming'the metal salt and thereafter esterifying the unreacted carboxylic acid groups.

Examples of basically reacting metal compounds useful in forming the n 1i xed,ester.-metal.salts of this'invention'are" 'sbdium oxide, sodium hydroxide, sodium carbonate, sodium methylate, sodium propylate, sodium pentylate, sodium phenoxide, potassium oxide, potassium hydroxide, potassium carbonate, potassium methylate, potassium ethylate, potassium pentylate, potassium phenoxide, lithium oxide, lithium hydroxide, lithium carbonate, lithium ethylate, calcium oxide, calcium hydroxide, calcium carbonate, calcium methylate, calcium ethylate, calcium propylate, calcium chloride, calcium fluoride, calcium pentylate, calcium phenoxide, calcium nitrate, barium oxide, barium hydroxide, barium carbonate, barium chloride, barium bromide, barium methylate, barium propylate, barium hexylate, barium nitrate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium ethylate, magnesium propylate, magnesium chloride, magnesium bromide, barium iodide, magnesium phenoxide, zinc oxide, zinc hydroxide, zinc carbonate, zinc meghylate, zinc propylate, zinc pentylate, zinc chloride, zinc nitrate trihydrate, cadmium oxide, cadmium hydroxide, cadmium carbonate, cadmium methylate, cadmium propylate, cadmium chloride, cadmium bromide, lead oxide, lead hydroxide, lead carbonate, lead ethylate, lead pentylate, lead chloride, lead iodide, lead nitrate, nickel oxide, nickel hydroxide, nickel carbonate, nickel chloride, nickel bromide, nickel methylate, nickel pentylate, nickel nitrate hexahydrate, cobalt oxide, cobalt hydroxide, cobalt bromide, cobaltous bromide, cobaltous chloride, cobaltous butylate, cobaltous nitrate hexahydrate, and the like. The above metal compounds are illustrative of those useful in this invention and the invention is not limited to the use of these particular metal compounds. Furthermore, mixtures of basically reacting metal compounds can be employed in the formation of the metal carboxylate groups, e.g., Ca(OH) and C00; Ca(OH) and Ba(OH) MgO and CaO; etc. When mixtures of basically reacting metal compounds of different metals are employed, the mixed ester-metal salts produced can contain two or more different metal cations.

The mixed ester-metal salts of this invention may be prepared by application of the conventional double decomposition procedure involving the reaction of the mixed ester-alkali metal salt with an inorganic metal salt selected from the class consisting of alkaline earth metal and lead, cadmium, zinc, nickel and cobalt, halides and nitrates. Such procedures are well-known in the art and require no detailed discussion herein.

Specific embodiments of my invention are presented in the following illustrative examples. Unless otherwise indicated, all references to percentages and parts are intended to refer to percent by weight and parts by weight in these examples as well as elsewhere in this present specification and claims.

EXAMPLE 1 A substantially hydrocarbon-substituted succinic anhydride is prepared by chlorinating a polyisobutene having a molecular weight of 1000 to a chlorine content of 4.5% and then heating the chlorinated polyisobutene with 1.2 molar proportions of maleic anhydride at a temperature of 150-220 C. The succinic anhydride thus obtained has an acid number of 130. A mixture of 874 grams (1 mole) of the succinic anhydride and 104 grams (1 mole) of neopentyl glycol is mixed at 240-250 C./ 30 mm. for 12 hours. The residue is a mixture of the esters resulting from the esterification of one and both hydroxy radicals of the glycol. It has a saponification number of 101 and an alcoholic hydroxyl content of 0.2%.

EXAMPLE 2 The dimethyl ester of the substantially hydrocarbonsubstituted succinic anhydride of Example 1 is prepared 12 by heating a mixture of 2185 grams of the anhydride, 480 grams of methanol, and 1000 cc. of toluene at 50-65 C. while hydrogen chloride is bubbled through the reaction mixture for three hours Ihe-mixture isthen e heatea a em es cfroi two hours, dissolved in benzene, Washed with water, dried and filtered. The filtrate is heated at 150 C./ 60 mm. to rid it of volatile components. The residue is the defined dimethyl ester.

EXAMPLE 3 EXAMPLE 4 A mixture of 926 grams of a polyisobutene-substituted succinic anhydride having an acid number of 121, 1023 grams of mineral oil, and 124 grams (2 moles per mole of the anhydride) of ethylene glycol is heated at 50170 C. while hydrogen chloride is bubbled through the reaction mixture for 1.5 hours. The mixture is then heated to 250 C./ 30 mm. and the residue is purified by washing with aqueous sodium hydroxide followed by washing with water, then dried and filtered. The filtrate is a 50% oil solution of an ester having a saponification number of 48.

EXAMPLE 5 A mixture of 438 grams of the polyisobutene-substituted succinic anhydride prepared as is described in Example l and 333 grams of a commercial polybutylene glycol having a molecular weight of 1000 is heated for ten hours at 150160 C. The residue is an ester having a saponification number of 73 and an alcoholic hydroxyl content. of 0.7%.

EXAMPLE 6 The acidic ester of Example 3 (2500 grams) is neutralized by mixing with 11 grams (10% excess on a chemical equivalent basis) of barium oxide, 20 grams of methanol, and 267 grams of mineral oil at 5060 C. The mixture is then heated to 150 C. to distill otf volatile components and the residue is filtered. The filtrate is a mineral oil solution of a mixed ester-metal salt having a saponification number of 17 and a barium sulfate ash content of 4.6%.

EXAMPLE 7 A mixture of 645 grams of the substantially hydrocarbon-substituted succinic anhydride prepared as is described in Example 1 and 44 grams of tetramethylene glycol is heated at -130 C. for two hours. To this mixture there is added 51 grams of acetic anhydride (esterification catalyst) and the resulting mixture is heated under reflux at' l30l60 C. for 2.5 hours. Thereafter the volatile components of the mixture are distilled by heating the mixture to 196270 C./30 mm. and then 240 C./ 0.15 mm. for ten hours. The residue is an acidic ester having a saponification number of 121 and an acid number of 58.

EXAMPLE 8 A mixed ester-metal salt is prepared as follows. A mixture of 1545 grams (1.5 moles) ofthe substituted succinic anhydride having an acid number of and prepared as is described in Example 1 and 46 grams (0.5 mole) of glycerol is heated at 150 C. for three hours whereupon the acid number of the reaction mixture is reduced to 68. It is then heated at -190 C. until the acid 13 number is reduced to 53. To this mixture there is added portionwise 125 grams (1.64 moles) of barium oxide together with 1500 grams of mineral oil and 50 cc. of water. The resulting mixture is heated to 90-100 C., diluted with 25 cc. of isopropyl alcohol and 100 cc. of benzene (solventmixture), and heated under reflux for three hours. Volatile components are then removed by heating the mixture to 160 C./35 mm. and the residue filtered. The filtrate is a mineral oil solution of the mixed ester-barium salt having a barium sulfate content of 5.6%.

EXAMPLE 9 A mixed ester-metal salt is prepared by the procedure of Example 8 except that pentaerythritol (51 grams, 0.38 mole) is used in place of glycerol. The product has a barium sulfate ash content of 4.9%.

EXAMPLE 10 A mixed ester-metal salt is prepared as follows. A mixture is prepared from 1545 grams (1.5 moles) of a polyisobutene-substituted succinic anhydride having an acid number of 110 and 152 grams (0.19 mole) of an ether-alcohol prepared by the reaction of sucrose with 8 moles of propylene oxide. The mixture is heated at 139-180 C. for three hours whereupon the acid number of the mixture is reduced to 45. It is diluted with 320 grams of mineral oil and heated at 170-195 C. for 3.5 hours until the acid number is 42. To this mixture there are added 1180 grams of mineral oil, 50 grams of water, 50 cc. of isopropanol, and 128 grams (0.83 mole) of barium oxide at 70 C. The resulting mixture is heated at 90-105 C. for three hours and dried at 158 C. The residue is filtered. The filtrate is a mineral oil solution of the mixed ester-barium salt having a barium sulfate ash content of 5.6%.

EXAMPLE 11 A mixture of 456 grams of a polyisobutene-substituted succinic anhydride prepared as is described in Example 1 and 350 grams (0.35 mole) of the monophenyl ether of a polyethylene glycol having a molecular weight of 1000 is heated at l50-155 C. for two hours. The product is an ester having a saponification number of 71, an acid number of 53. and an' alcoholic hydroxyl content of 0.52%.

EXAMPLE 12 EXAMPLE 13 A dioleyl ester is prepared as follows. A mixture of 1 mole of a polyisobutene-substituted succinic anhydride,

2 moles of a commercial oleyl alcohol, 305 grams of xylene, and gramsof p-toluene sulfonic acid (esterification catalyst) is heated at 150 -173 C. for four hours whereupon 18 grams of water is collected as the distillate. The residue is washed with water and the organic layer dried and filtered. The filtrate is heated to 175 C./20 mm. and the residue is the defined ester.

EXAMPLE 14 A dioleyl ester is prepared by the procedure of Example 13 except that the substituted succinic anhydride used is prepared by the reaction of a chlorinated petroleum oil having a molecular weight of 800 with maleic anhydride.

14 IEXAMPLE 15 An ether-alcohol is prepared by the reaction of 9 moles of ethylene oxide with 0.9 mole of a polyisobutene- .substituted phenol in which the polyisobutene substituent has a molecular weight of 1000. A substantiallyv hydrocarbon-substituted succinic acid ester of this ester-alcohol is prepared by heating a xylene solution of an equimolar mixture of the two reactants in the presence of a. catalytic amount of p-toluene sulfonic acid at 157 C. The ester is found to have a saponification number of 25 and an acid number of 10.

EXAMPLE 16 A polyhydric alcohol is prepared by copolymerizing equimolar proportions of styrene and allyl alcohol to a copolymerhaving a molecular weight of 1150 and containing an average of 5 hydroxyl radicals per mole. An ester of this alcohol is prepared as follows. A mixture of 340 grams (0.3 mole) of the alcohol and 1.5 moles of a polyisobutene-substituted succinic anhydride as is prepared in Example 1 in 500 grams of xylene is heated at 80-115 C., diluted with mineral oil, then heated to distill off xylene, and filtered. The filtrate is further esterified by heating with propylene oxide (one equivalent per equivalent of the unesterified anhydride) at 150 C. under reflux. The product is diluted with oil to an oil solution having an oil content of 40%.

EXAMPLE 17 A substantially hydrocarbon-substituted succinic acid is prepared by chlorinating a polyisobutene having a molecular weight of 50,000 to a chlorine content of 3.9% reacting the chlorinated polyisobutene with maleic anhydride to form a substituted succinic anhydride having an acid number of 20, and hydrolyzing the anhydride by treatment with steam at 102 -135 C. to the correspond ing acid. A mixture of 315 grams of the acid (0.06 mole) and 10 grams (0.17' mole) of propylene oxide is heated at 90-102 C. for one hour. The residue is then heated at 1001 10 C./1 mm. The above treatment with propylene oxide is repeated twice. The final product is found to have a saponification number of 20.

EXAMPLE 18 An ester of an ether-alcohol is prepared by heating a toluene solution of an equimolar mixture of the substantially hydrocarbon-substituted succinic anhydride of Example 1 and a commercial polyethylene glycol at 97- 102 C. for six hours and then at 110 C./16 mm. The ester has a saponification number of 37 and an acid number of 26.

EXAMPLE 19 A di-(hydroxypropyl)ester is prepared as follows: propylene oxide (58 grams, 1 mole) is added dropwise to a mixture of 0.5 mole of the substantially hydrocarbonsubsti'tuted succinic anhydride of Example 1 and 8 grams (0.1 mole, esterification catalyst) of pyridine at C. The mixture is heated at reflux for one hour, diluted with 400 grams of mineral oil and heated to 170 C./40 mm. The residue is filtered. The filtrate is a 40% mineral oil solution of the defined ester.

EXAMPLE 20 An ester is obtained by heating a mixture of 525 grams of the substantially hydrocarbon-substituted succinic anhydride of Example 1, 422 grams of butyl 9,10-epoxystearate, and 9.5 grams of pyridine (esterification catalyst) at -200 C. for 2.5 hours. The mixture is di- EXAMPLE 21 v hydride used) -A-40%'*mineral'oil "salaries or the ester obtained has a saponification number of 54 and an acid number of 0.4.

EXAMPLE 22 A partial ester of sorbitol is obtained by heating a xylene solution containing the substantially hydrocarbonsubstituted succinic anhydride of Example 1 and sorbitol (0.5 mole per mole of the anhydride) at 150-155 C. for six hours while Water is removed by azeotropic distillation. The residue is filtered and the filtrate is heated at 170 C./ 11 mm. to distill oif volatile components. The residue is an ester having a saponification number of 97 and an alcoholic hydroxyl content of 1.5%.

EXAMPLE 23 An ester is obtained by heating an equimolar mixture of dibutyl itaconate and chlorinated polyisobutene having a chlorine content of 4.7% and a molecular weight of 700 at 190-220 C. for seven hours and then at 200 C./ 3 mm. The residue is filtered. The filtrate is the ester havinga saponification number of 74.

EXAMPLE 24 An ester is obtained by the further esterification of sorbitol monooleate with a substituted succinic anhydride as follows: a mixture of 126 grams of sorbitol monooleate, 770 grams of the substantially hydrocarbon-substituted succinic anhydride of Example 1, 588 grams of minearl oil, .500 cc. of xylene and 9 grams of p-toluene sulfonic acid (esterification catalyst) is heated at 140 C., while Water is removed by azeotropic distillation. The residue is washed with water and dried at 150 C./20 mm. The product is a 40% mineral oil solution of an ester :having a saponification number of 68.

EXAMPLE 25 An ester is obtained by the procedure of Example 24 except that sorbitol trioleate (272 grams) is used in place of sorbitan monooleate. The product is a 40% oil solution of'the ester having a saponification number of 79.

EXAMPLE 26 A substantially hydrocarbon-substituted succinic anhydride is prepared as is described in Example 1 except that a copolymer of 90 weight percent of isobutene and 10- weight percent of piperylene having a molecular Weight of 66,000 is used in lieu of the polyisobutene used. The anhydride has an acid number of 22. An ester is prepared by heating a toluene solution of an equimolar mixture of the above anhydride and a commercial alkanol consisting substantially of C1244 alcohols at the reflux temperature for seven hours while water is removed by azeotropic distillation. The residue is heated at 150 C./ 3 mm. to remove volatile components and diluted with mineral oil. A 50% solution of the ester is found to have a saponification number of 17 and an acid number of 5.7.

EXAMPLE 27 A substantially hydrocarbon-substituted succinic anhydride having an acid number of 25 is obtained from maleic anhydride and a copolymer of 90 weight percent of isobutene with 10 Weight percent of piperylene having a molecular weight of 20,000. An ester of the above anhydride with allyl alcohol is prepared by heating a toluene solution containing the anhydride and allyl alcohol (4 moles per mole of the anhydride) in the presence of a catalytic amount of p-toluene sulfonic acid at 110125 C. The residue is then treated with calcium hydroxide and filtered. The solvent is then removed from the filtrate and .the residue is dissolved in a mineral oil to make up a 50% oil solution.

16 EXAMPLE 28 An ester is obtained by the procedure of Example 24 except that 234 grams of a poly(oxyethylene)substituted sorbitolamonooleate having a molecular weight'of 234 is used in place of sorbitol monooleate. The ester has a saponification number of 53.

EXAMPLE 29 (a) A mixture comprising 1028 parts of a polyisobutenyl-substituted succinic anhydride (average molecular Weight1028); prepared as in Example 1, 282 parts of phenol, 19 parts of toluenesulfonic acid monohydrate, and 514 parts of xylene is heated to reflux (153 C.) and maintained at this temperature for five hours. Thereafter, the mixture is cooled and 19 additional parts of toluenesulfonic acid esterification catalyst is added. Heating at reflux (153 154 C.) is continued for twenty-eight hours. The reaction mixture is then cooled to 50 C. and 7.5 parts of sodium hydroxide dissolved in 24 parts of Water is added. The resulting reaction mixture is then stripped at 68 C. at 21 mm. (Hg) and then at 223 C. at 21 mm. (Hg). The stripped product is then dissolved in 756 parts of mineral oil to produce an oil solution of the desired ester product. If desired, this oil solution can be filtered.

Following the general procedure of Example 29, the following hydroxy aromatic compounds (B) may be substituted for the phenol of Example 29 and reacted with the polyisobutenyl-substituted succinic acid anhydride (A) of Example 29 in the equivalent ratios indicated to produce additional ester products of the present invention.

TABIJE Hydroxy aromatic compound: Equivalent ratio :(AzB) Alpha-naphthol 1.1:1 4,4-methylene-bis-phenol 2:1 Di(hydroxyphenyl)oxide 1.5 :1 Propene tetramer-substituted phenol 1:1 Resorcinol 1:2 4-butylphenol 1:1.1 Alpha-decyl-beta-naphthol 1:1 Resorcinol 1:2

For further discussion of the esterification of hydroxy aromatic compounds, see R. D. Otfenhauer, The Direct 'Esterificationof Phenols, Journal of Chemical Education, Vol. 41, No. 1, page 39 (1964), and references cited therein.

EXAMPLE 30 A mixture comprising 1020 parts (1 mole) of a polyisobutenyl-substituted succinic anhydride prepared as described in .Example 1, and 1251 par-ts mineral oil diluent is heated to C. and 262 parts (1 mole) of a 70% solution of sorbitol is added over a five minute period. The resulting mixture is maintained at about 7280 C. for about 1.5 hours and then heated at about C. for six hours to complete the desired amount of esterification. Then 153 parts of barium oxide is added to the estercontaining reaction mixture over .75 hour While maintaining a temperature of about 8690 C. Then the resulting mixture is heated at 90-150 C. for three hours, -214 C. for four hours, and at about 214 C. for three hours. Water is removed by stripping the reaction mixture at reduced pressure and the mixture is filtered. The filtrate is a 55% oil solution of the desired mixed ester-metal salt product and is characterized by a sulfate ash content-of about 4.9%.

Following the general procedure of (a), polyisobutenylsubstituted succinic acid (A) of Example 29(a), sorbitol (B), and barium oxide (C) are reacted under the conditions indicated in the following table to produce other mixed ester-metal salts of this invention. The BaSO ash content is based on the total weight of filtrate which includes 50% mineral oil diluent except for Example 29(c) where the filtrate was adjusted to an oil content at about 52%.

Esten'fication Salt-forming reaction reaction Molar ratio Dura- Dura- BaSO ash Temp. tion Temp. tion content, (A):(B):(C) 0.) (hr.) 0.) (hr.) percent 90-95 1 (b)-.. 1.0.5.0.5 125 s{1 g} 4.6 (e)--. 1=o.17=1 150-197 8 58 g 5 6.8 90-9 1 (d)..- 1.0.2.1 140 s 2 I, 2.3

90-9 (6)... 1=0.2;0.5 153 s{ 210 6 4.9 (o. 11133.1 152 s 5% g 8.3

90-95 1 (h)-.- 1:o.25;1 135 s g 7g 1.9 1 1=o.25=o.5 145-150 8 i, 6 4.6

EXAMPLE 31 A mineral oil solution consisting essentially of about 44% mineral oil and the ester-containing reaction product produced by reacting polyisobutenyl-substituted succinic acid anhydride and pentaerythritol in a 1:1 mole ratio until the acid number of the esterification mixture indicates that all but about 15% of the carboxyl groups have been esterified is converted to a mixed ester-sodium salt by the following procedure: 1750 parts of the mineral oil solution of the ester is heated to about 150 C. and 125 parts of powdered sodium hydroxide is slowly added thereto. The resulting mixture is then heated at 150-160 C. for four hours while blowing nitrogen through the mixture to assist in water removal and thereafter filtered. The filtrate is an oil solution of the desired mixed ester-sodium salt and is characterized by a neutralization equivalent (phenophthalein) of about 4 (acid).

EXAMPLE 32 Following the general procedure set forth in US. Pat. No. 3,215,707 or No. 3,231,587, a polyisobutylene-Substituted succinic acid anhydride is prepared by heating a mixture of polyisobutylene having an average molecular weight of about 2100 with maleic anhydride in a mole ratio of polyisobutylene to anhydride of about 1:2 while passing chlorine through the reaction mixture. The re sulting polyisobutenyl-substituted succinic acid anhydride is mixed with mineral oil to produce a 42.5% oil solution of the anhydride, the solution being characterized by an acid number of about 52.

A mixture comprising 2350 parts of the oil solution of the above-described polyisobutenyl-substituted succinic acid anhydride and 151 parts of pentaerythritol is heated for about 3.5 hours while maintaining a temperature within the range of 177196 C. An additional 1254 parts of mineral oil is added to the esterification mixture and the resulting oil solution is heated for an additional hour at about 196 C. and then filtered. T-he filtrate is a 60% oil solution of the desired acidic ester.

Thereafter, 810 parts of the oil solution of the acidic ester produced above, 225 parts toluene, 10 parts water and 6.7 parts calcium oxide (CaO) is heated for seven hours while maintaining a temperature of about 109- 145 C. during which time 11.5 parts of water are removed azeotropically with the toluene. Thereafter 281 parts of additional mineral oil are heated and the product filtered. The filtrate is a 70% oil solution of the desired mixed ester-calcium sal-t characterized by a calcium sulfate ash content of about 1.14% by weight.

[EXAMPLE 3 3' A mixture, comprising 1190 parts of a polyisobutenylsubstituted succinic acid anhydride prepared by reacting chlorinated polyisobutylene (average molecular weight about 900) with maleic anhydride according to the general procedure of Example 1 and having an acid number of about 113, 41.8 parts of glycerol, and 500 parts mineral oil diluent are heated for eleven hours while checking the acid number every one to two hours to follow the course of esterification. When the neutralization equivalent of the mixture (phenophthalein) was 39 (acid), heating was terminated, the reaction mixture was cooled, and 700 parts additional oil diluent were added. Then, a previously formed slurry of 64 parts calcium hydroxide, 70 parts Water, 120 parts methanol is added to the esterification mixture while maintaining a temperature of about 50-60 C. The resulting mixture is then heated for two hours at -100 C., dried by heating to 106 C. and filtered. The filtrate is a 47% oil solution of the desired mixed ester-calcium salt characterized by a calcium sulfate ash content of 3.1%

EXAMPLE 34 A mixture comprising 1485 parts of the polyisobutenylsubStit-uted succinic acid anhydride described in Example 33, 79.5 parts of diethylene glycol, and 41 0' parts of mineral oil diluent are heated for seven hours While maintaining a temperature of about 143 1 80 C. Until the neutralization equivalent of the esterification mixture (phenophthalein) is 43 (acid). Thereafter, 1100 parts oil are added to the esterification mixture and the resulting mixture is cooled to 60 C. Subsequently, parts water, 80 parts methanol, and 73 parts calcium hydroxide are added to the mixture which is then heated for two hours at 80100 C. and heated to 160 C. to remove volatile materials and filtered. The filtrate is a 48.5% oil solution of the desired mixed ester-calcium salt and is characterized by a calcium sulfate ash content of about 3.2%.

EXAMPLE 35 C. for two hours and the product filtered. The filtrate is a 40% oil solution of the desired mixed ester-barium salt characterized by a sulfate ash content of about 2.8%.

EXAMPLE 3 6 An acidic ester is prepared by reacting triethanolamine with polyisobutenyl-substituted succinic acid anhydride having an average molecular weight of about 1000 in a mole ratio of anhydride to triethanolamine of 3: 1.5 until the neutralization equivalent (phenophthalein) of a 25% oil solution of the esterification product is about 24 (acid). The nitrogen content of the 25 oil solution of the esterification product is about 0.6%. Subsequently, 1850 parts of the oil solution, 500 parts of mineral oil, 50 parts water, and 50 parts methanol are heated to 60 C. at which point 61 parts barium oxide are added and the mixture heated for two hours at 60 C. Thereafter, volatiles are removed by heating to 150 C. and the resulting mixture is filtered. The filtrate is a 40% oil solution of the desired mixed ester-barium salt characterized by a barium sulfate ash content of about 3.5%.

EXAMPLE 37 A mixture comprising 1545 parts of polyisobutenylsubstituted succinic acid anhydride characterized by an acid number of about 770 parts of propylene glycol having an average molecular weight of about 1025, are heated for nine hours while maintaining a temperature within the range of -227 C. At that time, the neutralization number (phenophthalein) of the reaction mixture is 36 (acid). Then 1500 parts of oil are added and the resulting oil solution is cooled to 40 C. Fifty parts each of water and isopropyl alcohol are then added followed by 127 parts barium oxide. The resulting mixmixed ester-metal.saltland. is characterized by a bariunr sulfate ash content of about 4.8%.

EXAMPLE 38 Part 1 (a) To a mixture consisting of 3766 parts (7 moles of polyisobutenyl-substituted succinic acid anhydride) having an average molecular weight of about 1 080 and characterized by an acid number of about 104, 2567 parts mineral oil diluent, and 175 parts water, there is added 147 parts. (3.5 moles) lithium hydroxide monohydrate. The result-- ing mixture is heated under reflux for three hours at a temperature of about 1001l0 C. and then heated at.

(a) Then, a mixture consisting of 917 parts of the above oil solution of acidic salt and 68 parts (0.5 mole) pentaerythritol are heated for seven hours at 150-200 C. and filtered. The filtrate is a 38% oil solution of the desired mixed ester-lithium salt and is characterized by a sulfate ash content of about 2.8%{ and a neutralization equivalent of about 4.6 (acid).

(b) The general procedure of (a), Part 2 Was repeated but the amount of pentaerythritol was reduced to 34 parts (0.25 mole). The filtrate is characterized by a neutralization equivalent (acid) of about 3.8 and a sulfate ash content of about 3%.

(c) A mixture comprising 917 parts of the filtrate of (a), Part 2, and 75 parts (0.5 mole) of triethanolamine (N(CH CH 'OH) is heated for two hours at 85 -90 C. The reaction product is an oil solution of the desired mixed ester-metal. salt characterized by a neutralization equivalent of about 23 (acid), a sulfate ash content of about 2.8%, and a nitrogen content of about 0.7%.

(d) The procedure of (c) is repeated using 37 parts (0.25 mole) of alcohol. The product is characterized by a neutralization equivalent of about 24 (acid) a sulfate ash content of 2.8%, and a nitrogen content of 0.36%.

(e) The procedure of (c) is repeated but the mixture is heated for three hours with nitrogen blowing at 200 C. and filtered. The filtrate is a 38% oil solution of the desired mixed ester-metal salt characterized by a neutralization equivalent of about 2 (acid), a sulfate ash content of about 2.9%, and a nitrogen content of about 0.7%.

(f) The general procedure of (d) is repeated under the reaction condition specified in (e). The resulting filtrate is characterized by a neutralization equivalent of 2.6 (acid), a sulfate ash content of about 2.9%, and a nitrogen content of about 0.36%.

(g) A mixture comprising 802 parts of a 40% oil solution of an acidic salt prepared according to the general procedure of (a), Part 1, and 65 parts of ethylene oxide are heated for three hours at 90l00 C. and then stripped to 'a temperature of 100 C. and a pressure of 20 mm. (Hg). The stripped reaction product is a 37% oil solution of the desired mixed ester-metal salt characterized by a sulfate ash content of about 3%.

EXAMPLE 39 Part 1 (a) A polyisobutenyl-substituted succinic acid anhydride (2077 parts) as described in Example 33 and 247 parts pentaerythritol are mixed and heated for nine hours 20 While maintaining the temperature within the range of 170205 C. Then 1549 parts oil are added and heating is continued for 0.5 hour at l-200 C. and the resulting reaction mixture filtgredLThe filtrate is-a-4 0% oil solfitib'nTaf'tlie desired acidic ester and is characterized by a neutralization number (phenophthalein) of 15 (acid).

Part 2 A mixture comprising 910 parts of the above filtrate, 25 parts barium hydroxide monohydrate, 14 parts mineral oil, 10 parts water, 225 parts toluene and 1.5 parts methanol are heated for six hours while maintaining the temperature of the mixture within the range of 5891 C. The neutralization equivalent of the reaction mixture is substantially zero at that point. The reaction mixture is then heated from 91 to C. over a 3.5 hour period to azeotropically remove Water with the toluene. The mixture is then stripped to 135 C. and a pressure of 16 mm(Hg) and filtered. The filtrate is a 40% oil solution of the desired mixed ester-barium salt characterized by a sulfate ash content of about 3.2%.

(b) The general procedure of (a), Part 2, is repeated using no methanol and substituting 6.85 parts calcium oxide for the barium oxide monohydrate. The resulting filtrate is a 40% oil solution of the desired mixed estercalcium salt characterized by a neutralization equivalent of about 2 (acid) and a sulfate ash content of about 1.6%.

(c) The general procedure of (a), Part 2, is repeated using 4.9 parts of magnesium oxide in lieu of barium hydroxide monohydrate. Likewise 20 parts water and 20 parts methanol are employed in the reaction mixture. The filtrate is characterized by a sulfate ash content of about 1.6%.

(d) The general procedure of (a), Part 2, is repeated using 10 parts water, no methanol, parts toluene, and 27 parts lead oxide in lieu of barium hydroxide monohydrate. The filtrate is characterized by a lead content of 2.8%.

(e) A mixture of 988 parts of the filtrate of (a), Part 1, and 12.2 parts of zinc oxide are reacted according to the general procedure of (a), Part 2 but heated for ten hours at 80-130 C. The filtrate is characterized by a zinc content of 0.6%. Another procedure for preparing the zinc salt would be through the double decomposition reaction with zinc chloride after first forming an alkali metal salt.

EXAMPLE 40 (a) A mixture comprising 1084 parts of a polyisobutenyl-substituted succinic acid anhydride as described in Example 33, 41 parts zinc oxide, and 18 parts water are heated at 90-100 C. for three hours under reflux conditions. The reaction mixture is heated to 150 C. with nitrogen blowing to remove water. Then 34 parts of pentaerythritol are added and the mixture is heated at 200 C. with nitrogen blowing for five hours. The reaction mixture is filtered producing as a filtrate a 40% oil solution of the desired mixed ester-zinc salt characterized by a zinc content of about 1.4% and a neutralization equivalent (phenophthalein) of 31 (acid).

(b) A mixture of 1110 parts of polyisobutenyl-substituted succinic acid anhydride as described in Example 33, 762 parts mineral oil, and 34 parts pentaerythritol are heated at 190-200 C. for seven hours with nitrogen blowing and cooled to 70 C. Then 18 parts isopropanol and 18 parts of water are added. The mixture is heated to 90 C. and 41 parts zinc oxide are added. After heating the resulting mixture for four hours under reflux conditions at 90-95 C., it is dried by heating to 150 C. and filtered. The filtrate is a 40% oil solution of the desired mixed-ester characterized by a zinc content of about 1% and a neutralization equivalent (phenophthalein) of 23 (acid).

succinic acid acylating agents described hereinbefore. The

substitution of these other reactants is Within the skill of the art, particularly in view of the examples and discussion presented herein and the fact that the formation of carboxylic acid esters and metal carboxylates involve conventional processes.

The esters of this invention are useful for a wide variety of purposes, as pesticides, plasticizers, rust-inhibiting agents, corrosion-inhibiting agents, extreme pressure agents, detergents, etc.

A principal utility of the esters is as additives in lubricants. It has been discovered in accordance with this invention that when used for such purpose the esters depend for their effectiveness upon the size of the substantially hydrocarbon substituent in the succinic radical. More particularly, it has been found that esters in which the substantially hydrocarbon substituent contain more than about fifty aliphatic carbon atoms are effective to impart detergent properties to a lubricant, especially under low temperature, or intermittently high and low temperature, service conditions. It has been further found that the detergent properties of the esters diminish sharply when the size of this substituent is less than about fifty aliphatic carbon atoms, so that esters having less than about thirty-five aliphatic carbon atoms in this substituent are relatively ineffective for the purposes of this invention.

The lubricating oils in which the esters of this invention are useful as additives may be of synthetic, animal, vegetable, or mineral origin. Ordinarily, mineral lubricating oils are preferred by reason of their availability, general excellence, and low cost. For certain applications, oils belonging to one of the other three groups may be preferred. For instance, synthetic polyester oils such as didodecyl adipate and di-2-ethylhexyl sebacate are often preferred as jet engine lubricants. Normally, the lubricating oils preferred will be fluid oils ranging in viscosity from about 40 Saybolt Universal Seconds at 100 F. to about 200 Saybolt Universal Seconds at 210 The additives of this invention can be eifectively employed in a variety of lubricating compositions based on diverse oils of lubricating viscosity such as a natural or synthetic lubricating oil, or suitable mixtures thereof. The lubricating compositions contemplated include principally crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines including automobile and truck engines, two-cycle engine lubricants, aviation piston engines, marine and railroad diesel engines, and the like. However, automatic transmission fluids, transaxle lubricants, gear lubricants, metal-working lubricants, hydraulic fluids, and other lubricating oil and grease compositions can benefit from the incorporation of the present additives.

Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as solvent-refined or acidrefined mineral lubricating oils of the paraffinic, naphthenic or mixed parafiinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful base oils. Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, etc.); alkyl benzenes (e.g., dodecylbenzenes, tetradecylbenzene, dinonylbenzenes, di- (Z-ethylhexyDbenzeneS, etc.); polyphenyls (e.g., biphenyls, terphenyls, etc.) and the like. Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils. These are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of. these polyoxyalkylene polymers (e.g., methylpolyisopropylene glycol ether having an average molecular weight of 1000, diphenyl ether of polyethylene glycol having a molecular weight of 5004000, diethyl ether of polypropylene glycol having a molecular weight of 1000-0, etc.) or monoand polycarboxylic esters thereof, for example, the acetic acid esters, mixed C -C fatty acid esters, or the C oxo acid diester of tetraethylene glycol. Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, Z-ethylhexyl alcohol, pentaerythritol, etc.). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-nhexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of Z-ethylhexanoic acid, and the like. Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoXy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants (e.g., tetraethyl-silicate, tetraisopropyl-silicate, tetra-(Z-ethylhexyl)-silicate, tetra- (4-methyl-2-tetraethyl)-silicate, tetra-(p-tert butylpheny1)-silicate, hexyl-(4-methyl--2-pentoxy)disiloxane, poly- (methyl)-siloxanes, poly(methylphenyl)-siloxanes, etc.). Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid, etc.), polymeric tetrahydrofurans, and the like.

The concentration of the esters as additives in lubricants usually ranges from about 0.01% to about 10% by weight. The optimum concentration for a particular application depends to a large extent upon the type of service to which the lubricants are to be subjected. Thus, for example, lubricants for use in gasoline engines may contain from about 0.5 to about 5% of the additive whereas lubricating compositions for use in gears and diesel engines may contain as much as 10%, 15% or even more of the additive.

This invention contemplates also the presence of other additives in the lubricating compositions. Such additives include, for example, supplemental detergents of the ash containing type, viscosity index improving agents, pour point depressing agents, anti-foam agents, extreme pressure agents, rust-inhibiting agents, and supplemental oxidation and corrosion-inhibiting agents.

The ash-containing detergents are exemplied by oilsoluble neutral and basic salts of alkali or alkaline earth metals with sulfonic acids, carboxylic acids, or organic phosphorus acids characterized by at least one direct carbon-to-phosphorus linkage such as those prepared by the treatment of an olefin polymer (e.g., polyisobutene having a molecular Weight of 1000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and sulfur halide, or phosphorothioic chloride. The most commonly used salts of such acids are those of sodium, potassium, lithium, calcium, magnesium, strontium, and barium.

The term basic salt is used to designate the metal salts wherein the metal is present in stoichiometrically larger amounts than the organic acid radical. The commonly employed methods for preparing the basic salts involves heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate, bicarbonate, or

sulfide at a temperature about 50 C. and filtering the resulting mass. The use of a promoter in the neutralization step to aid the incorporation of a large excess of metal likewise is known. Examples of compounds useful as the promoter include phenolie substances-such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol, thiophenol, sulfurized alkylphenol, and condensation products of formaldehyde with a phenolic substance, alcohols such as methanol, 2-propanol, octyl alcohol, Cellosolve, Carbitol, ethylene glycol, stearyl alcohol, and cyclohexyl alcohol; amines such as aniline, phenylenediamine, phenothiazine, phenyl-beta-naphthylamine and dodecylamine. A particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic alkaline earth metal neutralizing agent, a phenolic promoter compound, and a small amount of water and carbonating the mixture at an elevated temperature such as 60200- C.

The preparation of a basic sulfonate detergent is illustrated as follows: A mixture of 490 parts (by weight) of a mineral oil, 110 parts of water, 61 parts of heptylphenol, 340 parts of barium mahogany sulfonate, and 227 parts of barium oxide is heated at 100 C. for 0.5 hour and then to 150 C. Carbon dioxide is then bubbled into the mixture until the mixture is substantially neutral. The mixture is filtered and the filtrate found to have a sulfate ash content of 25%.

The preparation of a basic barium salt of a phosphorus acid is illustrated as follows: A polyisobutene having a molecular weight of 50,000 is mixed with 10% by Weight of phosphorus pentasulfide at 200 C. for six hours. The resulting product is hydorlyzed by treatment with steam at 160 C. to produce an acidic intermediate. The acidic intermediate is then converted to a basic salt by mixing with twice its volume of mineral oil, 2 moles of barium hydroxide and 0.7 mole of phenol and carbonating the mixture at 150 C. to produce a fluid product.

The ester of this invention are especially adapted for use in combination with extreme pressure and corrosioninhibiting additives such as metal dithiocarbamates, xanthates, the Group II metal phosphorodithioates and their epoxide adducts, hindered phenols, sulfurized cycloalkanes, di-alkyl polysulfides, sulfurized fatty esters, phosphosulfurized fatty esters, alkaline earth metal salts of alkylated phenols, dialkyl phosphites, triaryl phosphites, and esters of phosphorodithioic acids. Combinations of the esters of this invention with any of the above-mentioned additives are especially desirable for use in lubricants which must have superior extreme pressure and oxidation-inhibiting characteristics.

The Group II metal phosphorodithioates are the salts of acids having the formula R2 S H in which R and R are substantially hydrocarbon radicals. The metals for forming such salts are exemplified by barium, calcium, strontium, zinc, and cadmium. The barium and zinc phosphorodithioates are especially preferred. The substantially hydrocarbon radicals in the phosphorodithioic acid are preferably low or medium molecular weight alkyl radicals and alkylphenyl radicals, i.e., those having from about one to thirty carbon atoms in the alkyl group. Illustrative alkyl radicals include methyl, ethyl, isopropyl, isobutyl, n-butyl, sec-butyl, the various amyl alcohols, n-hexyl methylisobutyl carbinyl, heptyl, 2- ethylhexyl, diisobutyl, isooctyl, nonyl, behenyl, decyl, etc. Illustrative lower alkylphenyl radicals include butylphenyl, amylphenyl, di-amylphenyl, octylphenyl, etc. Cycloalkyl radicals likewise are useful and these include chiefly cyclohexyl and the lower alkyl-cyclohexyl radicals. Other substantially hydrocarbon radicals likewise are useful such as tetradecyl, octadecyl, eicosyl, butylnaphthyl,

" "The availability of hexylnaphthyl, octylnaphthyl, cyclohexylphenyl, naph thenyl, etc. Many substituted hydrocrabon radicals may also be used, e.g., chloropentyl, dichlorophenyl, and dichlorodecyl. ,1, V M a. I a

the phosphorodithioic acids from which the Group II metal salts of this invention are prepared is well known. They are prepared by the reaction of phosphorus pentasulfide with an alcohol or phenol. The reaction involves four moles of the alcohol or phenol per mole of phosphorus pentasulfide, and may be carried out within the temperature range from about 50 C. to about 200 C. Thus the preparation of O,O-di-n-hexy1 phosphorodithioic acid involves the reaction of phosphorus pentasulfide with four moles of n-hexyl alcohol at about C. for about two hours. Hydrogen sulfide is liberated and the residue is the defined acid. The preparation of the zinc or barium salt of this acid may be effected by reaction with zinc oxide or barium oxide. Simply mixing and heating these two reactants is suflicient to cause the reaction to take place and the resulting product is sufficiently pure for the purposes of this invention.

Especially useful Group II metal phosphorodithioates can be prepared from phosphorodithioic acids which in turn are prepared by the reaction of phosphorus pentasulfide with mixtures of alcohols. The use of such mixtures enables the utilization of cheaper alcohols which in them selves do not yield oil-soluble phosphorodithioic acids. Thus a mixture of isopropyl and hexyl alcohols can be used to produce a very eifective, oil-soluble metal phosphorodithioate. For the same reason mixtures of simple phosphorodithioic (i.e., acids prepared from one alcohol) acids can be reacted with zinc oxide or barium oxide to produce less expensive, oil-soluble salts.

Another class of the phosphorodithioate additives contemplated for use in the lubricating compositions of this invention comprises the adducts of the metal phosphorodithioates described above with an epoxide. The metal phosphorodithioates useful in preparing such adducts are for the most part of the zinc phosphorodithioates. The epoxides may be alkylene oxides or arylalkylene oxides. The arylalkylene oxides are exemplified by styrene oxide, p-ethylstyrene oxide, alpha-methylstyrene oxide, 3-betanaphthyl-l,3-butylene oxide, m-dodecylstyrene oxide, and p-chlorostyrene oxide. The alkylene oxides include principally the lower alkylene oxides in which the alkylene radical contains six or less carbon atoms. Examples of such lower alkylene oxides are ethylene oxide, propylene oxide, 1,2-butene oxide, trimethylene oxide, tetramethyl-- ene oxide, butadiene monoepoxide, 1,2-hexene oxide, and propylene epichlorohydrin. Other epoxides useful herein include, for example, butyl 9,10-epoxy-stearate, epoxidized soya bean oil, epoxidized tung oil, and epoxidized copolymer of styrene with butadiene.

The adduct may be obtained by simply mixing the phosphorodithioate and the epoxide. The reaction is usually exothermic and may be carried out within wide temperature limits from about 0 C. to about 200 C. Because the reaction is exothermic it is best carried out by adding one reactant, usually the epoxide, in small increments to the other reactant in order to obtain convenient control of the temperature of the reaction. The reaction may be carried out in a solvent such as benzene, mineral oil, naphtha, or n-hexane.

The chemical structure of the adduct is not known. More than one mole, sometimes as many as four moles, of the epoxide can be made to combine with the phosphorodithioate to form products useful herein. However,

adducts obtained by the reaction of one mole of the phosphorodithioate with from about 0.25 mole to about 1 mole of a lower alkylene oxide, particularly ethylene oxide and propylene oxide, have been found to be especially useful and therefore are preferred.

The lubricating compositions may contain metal detergent additives in amounts usually within the range of from about 0.1% to about 20% by Weight. In some applica- Example II SAE 30 mineral lubricating oil containing 0.75% of the product of Example 2 and 0.1% of phosphorus as the barium salt of di-n-nonylphosphorodithioic acid.

Example III SAE 10W-30 mineral lubricating oil containing 0.4% of the product of Example 3.

Example IV SAE 90 mineral lubricating oil containing 0.1% of the product of Example 4 and 0.15% of the zinc salt of an equimolar mixture of di cyclohexyl phosphorodithioic acid and di-isobutyl phosphorodithioic acid.

Example V SAE 30 mineral lubricating oil containing 2% of the product of Example 12.

Example VI SAE 20W-30 mineral lubricating oil containing 5% of the product of Example 24.

Example VII SAE lW-30 mineral lubricating oil containing 1.5% of the product of Example 2 and 0.05% of phosphorus as the zinc salt of a phosphorodithioic acid prepared by the reaction of phosphorus pentasulfide with a mixture of 60% (mole) of p-butylphenol and 40% (mole) of npentyl alcohol.

Example VIII SAE 50 mineral lubricating oil containing 3% of the product of Example 26 and 0.1% of phosphorus as the calcium salt of di-hexylphosphorodithioate.

Example IX SAE 10W-30 mineral lubricating oil containing 2% of the product of Example 2, 0.06% of phosphorus as zinc di-n-octyl-phosphorodithioate, and 1% of sulfate ash as barium mahogany sulfonate.

Example X SAE 30 mineral lubricating oil containing 5% of the product of Example 10, 0.1% of phosphorus as the zinc salt of a mixture of equimolar amounts of di-isopropylphosphorodithioic acid and di-n-decylphosphorodithioic acid, and 2.5% of sulfate ash as a basic barium detergent prepared by carbonating at 150 C. a mixture comprising mineral oil, barium di-dodecylbenzene sulfonate and 1.5 moles of barium hydroxide in the presence of a small amount of water and 0.7 mole of octylphenol as'the promoter.

Example XI SAE W-30 mineral lubricating oil containing 6% of the product of Example 17, 0.075% of phosphorus as zinc di-n-octylphosphorodithioate, and 5% of the barium salt of an acidic composition prepared by the reaction of 1000 parts of a polyisobutene having a molecular weight of 60,000 with 100 parts of phosphorus pentasulfide at 200 C. and hydrolyzing the product with steam at 150 C.

26 Example XII SAE 10 mineral lubricating oil containing 2% of the product of Example 25, 0.075% of phosphorus as the adduct of zinc di-cyclohexylphosphorodithioate treated With 0.3 mole of ethylene oxide, 2% of a sulfurized sperm oil having a sulfur content of 10%, 3.5% of a poly-(alkyl methacrylate) viscosity index improver, 0.02% of a poly- (alkyl methacrylate) pour point depressant, 0.003% of a poly-(alkyl siloxane) anti-foam agent.

Example XII-I SAE 10 mineral lubricating oil containing 1.5 of the product of Example 14, 0.075% of phosphorus as the adduct obtained by heating zinc dinonyl-phosphorodithioate with 0.25 mole of 1,2-hexene oxide at C., a sulfurized methyl ester of tall oil acidhaving a sulfur content of 15%, 6% of a polybutene viscosity index improver, 0.005% of a poly-(alkyl methacrylate) anti-foam agent, and 0.5 of lard oil.

Example XIV SAE 20 mineral lubricating oil containing 1.5% of the product of Example 2, 0.5 of di-dodecyl phosphite, 2% of the sulfurized sperm oil having a sulfur content of 9%, a basic calcium detergent prepared by carbonating a mixture comprising mineral oil, calcium mahogany sulfonate and six moles of calcium hydroxide in the presence of an equimolar mixture (10% of the mixture) of methyl alcohol and n-butyl alcohol as the promoter at the reflux temperature.

Example XV SAE 10 mineral lubricating oil containing 25% of the product of Example 9, 0.07% of phosphorus as zinc dioctyl-phosphorodithioate, 2% of a barium detergent prepared by neutralizing with barium hydroxide the hydrolyzed reaction product of a polypropylene (molecular weight of 2000) with one mole of phosphorus pentasulfide and one mole of sulfur, 3% of a barium sulfonate detergent prepared by carbonating a mineral oil solution of mahogany acid, and a 500% stoichiometrically excess amount of barium hydroxide in the presence of phenol as the promoter at 180 C., 3% of a supplemental ashless detergent prepared by copolymerizing a mixture of 95% (Weight) of decyl-methacrylate and 5% (weight) of diethylaminoethylacrylate.

Example XVI SAE 80 mineral lubricating oil containing 2% of the product of Example 20, 0.1% of phosphorus as zinc din-hexyl-phosphorodithioate, 10% of a chlorinated paraffin wax having a chlorine content of 40% of di-butyl tetrasulfide, 2% of sulfurized dipentene, 0.2% olely amide, 0.003% of an anti-foam agent, 0.02% of a pour point depressant, and 3% of a viscosity index improver.

Example XVII SAE 10 mineral lubricating oil containing 3% of the product of Example 2, 0.075% of phosphorus as the zinc salt of a phosphorodithioic acid prepared by the reaction of phosphorus pentasulfide with an equimolar mixture of n-butyl alcohol and dodecyl alcohol, 3% of a barium detergent prepared by carbonating a mineral oil solu tion containing one mole of sperm oil, 06 mole of octylphenol, two moles of barium oxide, and a small amount of Water at C.

Example XVIII SAE 20 mineral lubricating oil containing 2% of the product of Example 12 and 0.07% of phosphorus as zinc di-n-octyl-phosphorodithioate.

Example XIX SAE 30 mineral lubricating oil containing 3% of the product of Example 14 and 0.1% of phosphorus as zinc diisobutyl-phenyl -phosphorodithioate.

27 Example XX SAE 50 mineral lubricating oil containing 2% of the product of Example 15.

.Example XXI I 90 mineral lubricating oil containing 3% of the product of Example 1 8 and 0.2% of phosphorus as the reaction product of four moles of turpentine with one mole of phosphorus pentasulfide.

Example XXII SHE 90 mineral lubricating oil containing 3% of the product of Example 19 and 0.2% of 4,4'-methylene-bis- (2,6-di-tert-butylphenol) Example XXIII SAE 30 mineral lubricating oil containing 2% of the product of Example 22 and 0.1% of phosphorus as phenylethyl dicyclohexylphosphorodithioate.

Example XXIV SAE 90 mineral lubricating oil containing of the product of Example 2 and 1% of the calcium salt of the sulfurized phenol obtained by the reaction of two moles of heptylphenol withone mole of sulfur.

By substituting the percentages of other esters of this invention for those of Examples IXXIV, still other lubricating compositions are readily prepared. For example, other mixed ester-metal salts as described herein can be substituted for those of Examples X and XV.

Fuel compositions are illustrated by the following compositions.

EXAMPLE XXV Gasoline containing 0.01% of the mixed ester-metal salt of Example 8.

EXAMPLE XXVI Kerosene containing 0.025% of the ester of Example 4.

EXAMPLE XXVlI Diesel fuel containing 0.075% of the mixed ester-metal salt of Example (c).

In fuels, hte esters of this invention promote fuel system cleanliness such as preventing the formation of deposits in fuel tanks, fuel lines, carburetors, fuel injection devices and, in many instances, reduce combustion chamber deposits, spark plug fouling, and exhaust valve deposits. They function effectively as anti-screen clogging agents. The esters are usually employed in normally liquid petroleum distillate fuels such as gasoline, diesel fuels, kerosene, aviation fuels, etc. They can be employed in concentrations of from about 0.001% to about 2% but usually will be present in amounts of 0.01% to about 0.5%. Obviously, the esters can be employed in conjunction with other conventional fuel additives such as deicers, smoke snppressants, anti-knock agents, metal scavengers, and the like.

The effectiveness of the esters of this invention as detergent additives in lubricating compositions is shown by the results in Table I of the modified CRC-EX-3 engine test (the modification consists of extending the test period from the specified 96 hours to 144 hours, thus making the test more severe). The test is recognized in the field as an important test by which lubricants can be evaluated for use under relatively lightduty or intermittently high and low'temperature service conditions such as are encountered in the operation of automobiles in urban use. In this test, the lubricant is used in the crankcase of a 1954 6- cylinder Chevrolet Power-glide engine operated for 144- hours under recurring cyclic conditions, each cycle consisting of: two hours at engine speed of 500 rpm. under no load, oil sump temperature of 100125 F., and air: fuel ratio of 10:1; and two hours at an engine speed of 2500 rpm. under a load of 40 brake horsepower, oil sump 28 temperature of 240-280 F., an an airzfuel ratio of 16:1. At the end of the test the lubricant is rated in terms of (1) the extent of piston filling, (2) the amount of sludge formed in the engine (rating scale of -0, 80 being indicative of SludgE an d O'being indicative of extremely heavy sludge) (3) the total amount of engine deposits, i.e., sludge and varnish formed in the engine (rating scale of -0, 100 being indicative of no deposit and 0 being indicative of extremely heavy deposits). The lubricting oil base used in the lubricants tested in a SAE 20 mineral lubricating oil.

uent is substantially saturated and contains at least about fifty aliphatic carbon atoms with the proviso that said hydrocarbon substituent can optionally contain polar groups provided the polar groups in total do not exceed about 10% by weight of the hydrocarbon portion of the hydrocarbon substituent, wherein the metal cation of the mixed ester-metal salt is selected from the class consisting of Group 1(a), Group II, and lead, nickel, cobalt, and aluminum cations.

2. A mixed ester-metal salt according to claim 1 wherein not more than about 2% of the carbon-to-carbon c0- valent linkages therein are unsaturated linkages.

3. A mixed ester-metal salt according to claim 2 wherein the alcohol moiety of the ester is derived from monoand polyhydric alcohols, phenols, and naphthols.

4. A mixed ester-metal salt according to claim 3 wherein the metal cation of said salt is a Group 1(a) or Group 11 metal cation.

5. A mixed ester-metal salt according to claim 4 wherein said hydrocarbon substituent is derived from a polyolefin having an average molecular weight of about 700 to about 5000'.

6. A mixed ester-metal salt according to claim 5 wherein the alcohol moiety contains up to about forty carbon atoms.

7. A mixed ester-metal salt according to claim 6 wherein the metal cation is an alkali or alkaline earth metal cation.

8. A mixed ester-metal salt according to claim 7 wherein the alcohol portion of the ester is derived from a polyhydric alcohol containing two to ten hydroxy groups.

9. A mixed ester-metal salt according to claim 8 wherein the hydrocarbon substituent is derived from a poly-1- monoolefin and the alcohol moiety is a polyhydric alkanol containing three to six hydroxy groups.

10. A mixed ester-metal salt according to claim 9 wherein the metal cation is an alkaline earth metal cation.

11. A mixed ester-metal salt according to claim 10 wherein the alcohol portion of the ester is derived from a member selected from the class consisting of glycerol, pentaerythritol, sorbitol, and mannitol.

12. A mixed ester-metal salt according to claim 11 wherein the hydrocarbon substituent is derived from polyisobutylene.

13. A mixed ester-metal salt according to claim 12 wherein the cation is a barium cation.

14. A mixed ester-metal salt according to claim 2 wherein the alcohol moiety is derived from a polyoxyalkylene alcohol containing up to about alkylene oxy groups and having from two to eight carbon atoms per alkylene group.

15. A mixed ester-metal salt according to claim 14 wherein the cation is a Group 1(a) or Group II metal cation.

16. A mixed ester-metal salt according to claim 15 wherein the hydrocarbon substituent is derived from a polyolefin having an average molecular weight of about 700 to about 5000 and the metal cation is an alkali or alkaline earth metal cation.

17. A mixed ester-metal salt according to claim 16 wherein the hydrocarbon substituent is derived from a poly(1-monoolefin) and the cation is an alkaline earth metal cation.

18. A mixed ester-metal salt ester according to claim 17 wherein the hydrocarbon substituent is derived from polyisobutylene, the alcohol moiety is derived from polyoxyethylene glycol or polyoxypropylene glycol, and the metal cation is barium.

19. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 1 sufficient to impart sludge-dispersing capabilities to said composition.

20. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 3 suflicient to impart sludge-dispersing capabilities to said composition.

21. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 7 sufiicient to impart sludge-dispersing capabilities to said composition.

22. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 9 sufficient to impart sludge-dispersing capabilities to said composition.

23. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 22 sufiicient to impart sludge-dispersing capabilities to said composition.

24. A lubricant or fuel composition comprising, respectively, a major amount of a lubricating oil or a normally liquid fuel, and an amount of a mixed ester-metal salt according to claim 14 suflicient to impart sludge-dispersing capabilities to said composition.

25. A lubricant composition comprising a major amount of a mineral lubricating oil and an amount of a mixed ester-metal salt according to claim 1 sufficient to impart sludge-dispersing capabilities to said composition.

26. A fuel composition comprising a major amount of a mineral lubricating oil and an amount of a mixed estermetal salt according to claim 1 sufficient to impart sludgedispersing capabilities to said composition.

References Cited UNITED STATES PATENTS 3,163,603 12/1964 Le Suer 25233.6 3,271,310 9/1966 Le Suer 252-39 X 2,292,308 8/1942 Watkins 252-39 X 2,294,259 8/1942 Van Peski et a1 260-485 2,363,516 11/1944 Farrington et al. 25233.6 X 2,773,897 12/1956 Bavley et a1. 260-485 X 2,980,615 4/1961 Morway et al. 252-41 3,285,945 11/1966 Wember 260-4299 3,485,858 12/1969 Gee et al M 44-68 X DANIEL E. WYMAN, Primary Examiner W. J. SHINE, Assistant Examiner US. Cl. X.R.

UNHED STATES PATENT OFFICE CERTIFICATE OF CURRECTFON Patent No. Y 5,632,510 Dated January 4; 1972 Inventor(s) Willi-aim M. LeSuer V It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below;

At colurnn 29, line 15, that is C1aim18, line 1 "mixed ester-metal salt ester" should be --mixed ester-metal sa1t--.

Signed and sealed this 12th day of March 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C.-, MARSHALL DANN Attesting Officer Commissioner of Patents FORM PC4050 uscoMM-Dc 6037B-P69 fl' US. GOVERNMENTPRINTING OFFICE: I959 0-366-33A UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIUN Patent No. EJ652251) Dated January 1972 Inventor(s) william'M- Lesuel" It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1 At column 30, line 3, that is, Claim 25, line 4,

Claim 22" should be -Claim l2-. Y

Signed and sealed this 29th day of August 1972.

(SEAL) Attest:

EDWARD M FLETCHER JR ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1OSO (10-69) USCOMM-DC scans-P69 fl lLS. GOVERNMENT PRINTING OFFICE: I969 O366334 

